Mexican American (MA) men report particularly low rates of physical activity (PA) and are disproportionately burdened by conditions related to sedentary lifestyle (e.g., diabetes, obesity). Due to cultural, SES, educational, and language differences, MA men may have limited access to public health interventions promoting PA. To address these rising health disparities, effective interventions that leverage state-of-the-art technology, theory, and methods are needed for MA men. Our research team has 25 years of experience developing and implementing individually tailored PA interventions. We culturally and linguistically tailored our print intervention for Latina women and then demonstrated its efficacy in two RCTs. This research experience leaves us well poised to address the PA-related health disparities in MA men. Due to the dearth of studies in this area, we conducted qualitative interviews with Spanish speaking MA men (N=10). Their feedback informed the modifications of our PA intervention as well as the creation of new materials, which were then tested in a demonstration trial with MA men (N=10). After 12 weeks, participants reported significant increases in weekly PA (Mean increase=124 minutes, sd=154.86, p =.03) with 100% retention. However, only 40% met the PA guidelines of 150 minutes/week and 30% did not adopt any activity, suggesting a more intensive intervention may be necessary. Follow-up interviews revealed that the men liked the print materials but also wanted greater accountability, more contact with staff and each other, shorter and more frequent tips, and more updates on activity opportunities. The men recommended adding a text message component to address these issues. Thus, the aim of this study is to build upon our tailored print intervention by developing new text-delivered intervention materials to complement our print-based intervention, which will now include printed tailored environmental reports. In Phase 1 we will conduct 6 focus groups with MA men to determine content, frequency, and types of text messages desired, and to identify cultural themes to incorporate into existing and new materials. Themes from the focus groups and sample text messages will be presented to a confirmatory panel. Phase 2 will be a 6-month pilot RCT with MA men (N=60) to test the text- enhanced, Spanish language, individually tailored PA intervention vs. publicly available, Spanish language health education materials, including information on PA, diet, and stress management. This will be followed by post-intervention qualitative interviews to solicit suggestions for improvements to help further refine the program. The proposed pilot will support a future R01 to establish the efficacy of this multi-media, multi-level PA intervention for MA men.